The Molecular Biology and Genetics Core Laboratory of the DRTC has been in operation since the grant was first funded in 1977 with minor changes in the name of the core but with a major emphasis on molecular biology and recently genetics. At the last competitive renewal, the Core was judged to have outstanding merit. This Core helps independently funded investigators with an interest in diabetes mellitus and other metabolic disorders to clone, sequence and characterize cDNAs and genes of interest. The Core also helps investigators who are interested in using genetic approaches to the study of metabolic diseases through isolation of DNA from blood, genotyping using microsatellite markers and single-nucleotide polymorphisms, and genetic analysis including tests for linkage and association. In the previous funding period, Dr. Donald Steiner was Director of this Core with Drs. Graeme Bell and Nancy Cox serving as Co-Directors. In the current application, Dr. Steiner has become Director of the DRTC and Dr. Bell is Director of the Molecular Biology and Genetics Core Laboratory with Drs. Cox and Gene Webb serving as Co-Directors. This is a natural transition for Dr. Bell who has been a Co-Director and user of this Core since joining the University of Chicago in 1986. A detailed progress report outlining the growth and effectiveness of The Molecular Biology and Genetics Core Laboratory of the DRTC follows.